Automatically adjustable passenger mirror assembly for a trailered vehicle having a mirror position feedback and position correction device

ABSTRACT

An automatic mirror rotation assembly is provided for a vehicle having a tractor and semi-detached trailer. A control wheel is mounted in a structure connecting to a chassis of the tractor, and is raised into engagement with a lower surface of the trailer. As the vehicle turns, the rotation of the trailer with respect to the tractor is measured by counting rotations or partial rotations of the wheel against the underside surface of the trailer. A corresponding degree of passenger-side rear view mirror is calculated, and a motor automatically rotates the mirror. A mirror position feedback device measures the actual rotation of the mirror and feeds that information back to the assembly. A mirror position correction device automatically adjusts the mirror position when an actual mirror position differs from a desired mirror position.

This application is a continuation in part of U.S. application Ser. No.08/769,005, filed on Dec. 18, 1996, now U.S. Pat. No. 5,953,167, whichis a continuation in part of U.S. application Ser. No. 08/385,448, filedon Feb. 8, 1995, and issued as U.S. Pat. No. 5,627,688.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an assembly for automatically rotating avehicle rear view mirror. More specifically, the invention relates bothto an assembly for automatically rotating a rear view mirror mounted oneither side of a vehicle comprising a tractor hauling a semi-detachedtrailer, and to the rear view mirror itself.

2. Description of the Related Art

Trailered vehicles are well-known. Referring to FIG. 1a, a traileredvehicle 20 comprises a semi-detached trailer 22 mounted to a tractor 24.Trailer 22 is mounted at a hitching point 26, typically referred to as a“fifth wheel,” positioned at a rear end 28 of the tractor's chassis 30.The tractor and trailer generally align to define an imaginary axis 32.A passenger-side rear view mirror 34 typically is mounted on apassenger-side door of the tractor, and positioned generally inalignment with the axis 32, so that the driver can see thepassenger-side rear corner 36 of the trailer 22. The driver typicallyadjusts this passenger-side mirror 34 either electrically, or by hand,according to the length of the trailer 22. The driver's field of visionin the passenger-side mirror is depicted by reference numeral 38. Theabove-described relationship is shown in FIG. 1(a), depicting the righthand side as the passenger side, as is common for example in NorthAmerica and continental Europe. Alternatively, a reversed relationshipapplies in other countries where the passenger side is on the left handside.

A problem occurs when the driver enters a turn, either going forward orreversing. As the tractor turns, the trailer pivots with respect to thetractor, forming an angle therebetween. The passenger-side rear viewmirror, however, remains stationary. The trailer 22 therefore blocks thefield of vision 38, causing the driver to lose sight of thepassenger-side rear corner 36 of the trailer, along with any object inthe vicinity. This problem is depicted in FIG. 1(b). Tighter turnsobviously exacerbate this problem.

The resultant loss of rear visibility creates potentially dangeroussituations. Whether driving on winding roads, or attempting to back thetrailer into a parking lot or a loading dock, the driver's inability tosee other vehicles, persons, or other objects in his passenger-sidemirror can result in property damage or more serious accidents.

Reports published in 1994 indicate that out of 330,000 reported truckcrashes in the U.S. in 1991, 19.1% of these accidents involved backing,turning, lane-changing, or merging maneuvers by trailered vehicles.These crashes accounted for 1.0% of all fatalities, 10.8% of injuries,and 6.3% of costs for trailered vehicle accidents that year, with totaldirect monetary losses estimated at over $250 million.

A number of commercially available warning systems exist that give adriver a warning of objects behind his truck during a turn. Despite thedesirability of such systems, surveys of professional truck drivers havenoted several shortcomings with the available systems. For example,existing devices are not easy to install. Another problem exists withthe reliability of the existing systems, including damage to the systemswhile in use. Another problem is the difficulty of using the existingsystems. In short, existing systems to detect and warn drivers ofobjects behind a truck have limited areas of coverage, provideinconsistent warnings, and rarely are used.

A better solution is to enable the driver to rely on his passenger-siderear view mirror by providing the mirror with the capability to rotatein response to a vehicle turn. Past attempts to provide such a devicehave met with limited success, as evidenced by the fact that no suchdevice is in widespread use in the trucking industry.

An automatically adjustable passenger-side rear view mirror assembly isdesired for trailered vehicles that is easy to install and operate, andis reliable under normal truck-driving conditions and environments.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe combinations described in the attached claims.

SUMMARY OF THE INVENTION

To achieve the foregoing objects, and in accordance with the purposes ofthe invention as embodied and broadly described herein, a mirrorrotation assembly is provided for a vehicle having a tractor and apivotally connected semi-detached trailer. The assembly comprises anapparatus supporting a rotatable control wheel, attachable to thetractor chassis proximate the fifth wheel. The control wheel supportapparatus is configured to move the control wheel from a disengagedposition proximate the chassis, to an engaged position with the wheel inrolling contact with an underside of the trailer. A counting means isprovided that is operable to count a number of rotations or partialrotations of the wheel as the trailer pivots with respect to the tractorduring a vehicle turn. A motor connects to a rotatable mirror on thetractor. A control means also is provided, programmed to receive thenumber of wheel rotations or partial rotations from the counter,calculate a degree of vehicle turn corresponding to the number of wheelrotations or partial rotations, calculate a degree of mirror rotationcorresponding to the degree of vehicle turn, generate a signalindicating a desired mirror position.

In one preferred embodiment, the control wheel support apparatusincludes a mounting block having a groove defined therein, a sliderblock slidably mounted in the groove, the control wheel mounted on theslider block, and a spring for biasing the slider block upward so thatthe control wheel engages the underside of the trailer.

In another embodiment, the control wheel support mechanism includes anarm that pivots upward until the control wheel engages the underside ofthe trailer.

Other structures capable of supporting the control wheel, and bringingthe control wheel into and out of engagement with the underside of thetrailer are also possible.

It is preferred that the mirror include a position feedback device. Themirror position feedback device determines an actual mirror position andgenerates an actual mirror position signal indicating an actual mirrorposition.

It is further preferred that the mirror include a mirror positioncorrection device. The mirror position correction device compares theactual mirror position signal from the mirror position feedback deviceto the calculated mirror position signal indicating a desired mirrorposition from the control means. The correction device then corrects themirror position when the actual mirror position signal differs from thecalculated mirror position signal.

DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will be described indetail below with reference to the accompanying drawings. Together withthe general description given above and the detailed description of thepreferred embodiments given below, the drawings serve to explain theprinciples of the invention.

FIG. 1(a) is a top view of a trailered vehicle including a tractor and asemi-detached trailer, depicting the normal field of vision of apassenger-side rear view mirror;

FIG. 1(b) is a top view of a tractor and semi-detached trailer of theprior art, in which the field of vision in the passenger-side rear viewmirror is reduced or eliminated during a vehicle turn;

FIG. 1(c) is a top view of a tractor and semi-detached trailer includingan automatically adjustable rear view mirror assembly according to thepresent invention, in which the driver retains the field of vision inthe passenger-side rear view mirror during a vehicle turn;

FIG. 2 is a side view of a first embodiment of a mirror rotationassembly according to the present invention;

FIG. 3 is another side view of the first embodiment of a mirror rotationassembly shown in FIG. 2;

FIG. 4 is a front view of the first embodiment of a mirror rotationassembly shown in FIG. 2;

FIG. 5 is a side view of certain components of a second embodiment of amirror rotation assembly according to the present invention;

FIG. 6 is a top view of the embodiment of the mirror rotation assemblycomponents depicted in FIG. 5;

FIG. 7 is a top schematic view depicting the placement of a controlmeans and wiring according to the present invention;

FIG. 8 is a side view of a vehicle tractor depicting placement of mirrorrotation assembly components;

FIG. 9 is a front view of a control panel used with the presentinvention, located in the cab of the vehicle tractor;

FIG. 10 is a side view of a mirror assembly used with the presentinvention;

FIG. 11 is a front view of the mirror assembly shown in FIG. 10;

FIG. 12 is a top view of the mirror assembly shown in FIG. 10;

FIG. 13 is a detailed front view of a mirror assembly having adetachable mirror face, which can be used with the present invention;

FIG. 14 is a perspective view of a mirror assembly with a positionfeedback device attached to the frame;

FIG. 15 is a cutaway side view of a mirror position feedback device inaccordance with the invention;

FIG. 16 is a schematic diagram of a mirror position correction device inaccordance with the invention;

FIG. 17 is a schematic plan view illustrating a set home field of viewof left and right hand sideview mirrors of a truck traveling on a fivelane highway; and

FIG. 18 is a schematic plan view illustrating a typical scanningsetpoint field of view of left and right hand sideview mirrors of atruck traveling on a five lane highway.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the presently preferredembodiments of the invention as broadly illustrated in the accompanyingdrawings.

A mirror rotation assembly is provided for a vehicle having a tractorand a pivotally connected semi-detached trailer. Referring to FIG. 1a, avehicle 20 includes a trailer 22 which connects pivotally to a tractor24 at a pivot point 26 commonly known in the trucking industry as the“fifth wheel.” The fifth wheel 26 is positioned proximate a end 28 oftractor chassis 30. The tractor and trailer align to define an imaginaryaxis 32. A rear view mirror 34 is provided on the passenger-side door,to provide the driver a field of vision 38 encompassing thepassenger-side rear corner 36 of the trailer. The overall configurationof a trailered vehicle, and the attachment between the trailer and thetractor, are well known and will not be described further.

In accordance with a first embodiment of the invention, a mounting blockis provided, attachable to the chassis, and having a groove definedtherein. As shown in FIG. 2, a mounting block 200 attaches to tractorchassis 30 proximate a front end of fifth wheel 26. Preferably, mountingbolts 202 attach mounting block 200 directly to fifth wheel 26. In apreferred embodiment, mounting block 200 is made of a non-corrosivematerial, preferably aluminum, having approximate dimensions of 3″×3½″.As shown in FIG. 4, a groove 204 is provided in mounting block 200.

In accordance with the first embodiment of the invention, a controlwheel is slidably supported in the groove. As shown in FIGS. 2-4, aslider block 206 slidably engages groove 204. Slider block 206 includesat least one, and preferably two, projecting arms 208. Projecting arms208, and consequently slider block 206, are biased in an upwarddirection (as shown in FIG. 4) by coil springs 210 mounted on shafts212. As shown in FIGS. 2 and 3, a generally U-shaped bracket 214attaches to slider block 206, the bracket 214 supporting an axle 216.Control wheel 58 is rotatably supported on axle 216.

As noted above, coil springs 210 bias slider block 206 in an upwarddirection, thereby biasing control wheel 58 upward to an engagedposition in contact with the bottom surface of trailer 22. The springforce of coil springs 210 should be adequate to maintain the controlwheel 58 in engagement with trailer 22 despite jolts caused byirregularities in the road surface.

As embodied in FIGS. 2-4, control wheel 58 is mounted on U-shapedbracket 214 and axle 216 at a preselected angle θ with respect to avertical line Z—Z drawn between the bottom surface of trailer 22 and theground. It has been found that because control wheel 58 travels in anarc along the underside of trailer 22 when trailer 22 pivots, controlwheel 58 can roll more easily if it is angled with respect to a verticalline, and therefore also with respect to the horizontal bottom surfaceof the trailer. The preferred angle θ of control wheel 58 with respectto vertical line Z—Z may be, for example, in a range of 5°-15° dependingon the configuration of the vehicle. It is further preferred that theedge of control wheel 58, which will contact the underside surface oftrailer 22 due to the 15° offset, be chamfered to increase the amount ofwheel surface in contact with the trailer.

In accordance with the first embodiment of the invention, a counter isprovided, operable to count a number of rotations or partial rotationsof the control wheel as the trailer pivots with respect to the tractorduring a vehicle turn. As shown in FIGS. 3 and 4, an electronic countingmechanism 220 is attached to slider block 206. Counter 220 is configuredto count the rotations or partial rotations of wheel 58. Alternatively,wheel 58 can be fixed to a rotating axle 216, in which case counter 220can be configured to count the rotations or partial rotations of axle216. The number of rotations are translated into counts, which aretransmitted via wires 96 to the control means, described below.

In accordance with the first embodiment of the invention, the controlwheel is movable away from the bottom surface of the trailer when thetrailer is disengaged from the chassis of the tractor. A slidingmechanism is provided with fifth wheel 26 for releasing the engagementbetween trailer 22 and tractor 24. The sliding mechanism may beconstructed of a combination of a release lever, a shaft, and a rotatingcam, as shown in FIG. 2, or a piston with a fluid cylinder (not shown),or any other equivalent mechanism. A release lever 230 is provided withfifth wheel 26 for releasing the engagement between trailer 22 andtractor 24. Preferably, a second release lever 232 is attachable to thefifth wheel release lever 230. Release lever 232 in turn attaches to ashaft 234, which is coupled to a rotating cam 236 on mounting block 200.A cable 238 extends between cam 236 and a cable set screw 240 bolted toslider block 206. When the driver operates the fifth wheel release lever230, second release lever 232 turns shaft 234, which rotates cam 236.Rotation of cam 236 pulls cable 238, which in turn applies a downwardforce to slider block 206 against the upward bias of coil springs 210.The downward pull of cable 238 slides slider block downward along groove204, thereby disengaging control wheel 58 from trailer 22, and movingcontrol wheel 58 down away from trailer 22. This sequence functions tomove the control wheel 58 clear of trailer 22, thereby avoiding thepossibility of being damaged during disengagement of trailer 22 fromtractor 24.

The first embodiment provides for sliding movement of slider block 206in groove 204 of mounting block 200. To assist this sliding movement, alubricant such as graphite may be inserted into groove 204. It wouldalso be within the scope of the invention to provide bearings or wheelsbetween slider block 206 and groove 204, to create a rolling motion. Themechanism to engage control wheel 58 to the bottom surface of trailer 22may have different configurations, including configurations having asliding motion, a rolling motion, or a pivoting motion, either by waysof a spring action, a pneumatic action, or any other. This inventioncovers all these mechanical configurations.

The invention is not limited to the use of a mounting block attachableto the chassis for pivoting the control arm to an engaged position.Rotation of the trailer is sensed by rotation of control wheel 58against the bottom surface of the trailer as the trailer turns.Rotations of the control wheel 58 are then counted for later translationinto a corresponding degree of trailer rotation. Hence, any structurecapable of bringing the control wheel 58 into engagement with the bottomsurface of the trailer falls within the scope of the present invention.

A second embodiment of a structure capable of engaging the control wheelwith the bottom surface of the trailer is described below.

In the second embodiment of the invention, an elongated arm having firstand second ends is provided. The first end is pivotally mountable to asupport on the chassis of the tractor with the arm generally transverseto an axis defined by the tractor and the trailer. The second endsupports a rotatable wheel. As broadly depicted in FIG. 5, a support 40is attachable to a plurality of positions on the tractor chassis.Preferably, support 40 is a steel cross member 42 mountable to channels29 in the chassis at a number of selected positions in front of fifthwheel 26, using steel hold down clamps 44, bolts 46, and neoprenegaskets 48. Clamps 44 preferably are steel clamps. The use of clamps andbolts to secure cross member 42 to chassis 30 allows the driver toloosen the bolts and move the cross-member 42 to the desired position,depending on the particular trailer being towed. One of ordinary skillin the art will recognize that most commercial trailers in the UnitedStates have a steel plate with holes in it mounted on the underside ofthe trailer, either 12 inches or 22 inches in front of the fifth wheel.The position of the cross member 42 on the chassis therefore should beadjustable as necessary to avoid holes in this plate. Neoprene gaskets48 allow for variations in chassis surfaces.

As further broadly depicted in FIG. 5, an elongated control arm 50 has afirst end 52 and a second end 54. First end 52 attaches pivotally tosupport 40 at pivot point 56. A control wheel 58, preferably including amolded rubber tire having a maximum capacity of 400 psi, is rotatablymounted at pivot point 60 at second end 54 of control arm 50.

In accordance with the second embodiment of the invention describedabove, a pivot assembly is provided to pivot the arm from a disengagedposition proximate the chassis to an engaged position with the wheel inrolling contact with an underside of the trailer. As broadly depicted inFIG. 5, a cylinder 62, preferably a dual-action pneumatic cylinder, ispivotally connected to support 40 at pivot point 64. Piston rod 66projects from cylinder 62, and is pivotally connected to control arm 50at pivot point 68, intermediate first end 52 and second end 54.

As broadly embodied in FIG. 5, pressurized fluid is provided to actuatecylinder 62 via a fluid line 70. Preferably, 15 psig is supplied tocylinder 62 via the fluid line 70. In the preferred embodiment, thepressurized fluid is compressed air, preferably supplied by thevehicle's air compressor, via a solenoid control valve 72. This can bethe same compressed air used in the vehicle brake system. However, it iswithin the scope of the invention to provide a separate pneumatic systemto operate cylinder 62.

In accordance with the second embodiment of the invention, control arm50 and cylinder 62 are positioned on support 40 so that when cylinder 62is pressurized, control arm 50 will be pivoted upward from a disengagedposition 80 proximate the chassis, to an engaged position 82 with wheel58 in rolling contact with the underside surface of trailer 22.Moreover, in accordance with the invention, these components arepositioned so that the arc 84 defined by the arm's motion fromdisengaged position 80 to engaged position 82 is transverse to the axis32 defined by the aligned tractor and trailer. The reason for thispositioning will be apparent from the description of the operation ofthe invention given below.

It is also preferable that when control arm 50 of the second embodimentis in the engaged position 82, wheel 58 be maintained in substantiallycontinuous rolling contact with the underside of trailer 22. Thisfeature of the invention takes into account normal road conditions,which will cause trailer 22 to move up and down as the vehicle wheelsencounter bumps in the road. In order to help maintain thissubstantially continuous contact, a regulator 86 preferably is providedin fluid line 70 to adjust the pressure in cylinder 62 as necessary toadjust the position of control arm 50 and keep control wheel 58 incontact with trailer 22. Preferably, regulator 86 will operate tomaintain substantially constant pressure in cylinder 62.

In accordance with the second embodiment of the invention, a counter isprovided, operable to count a number of rotations or partial rotationsof the wheel as the trailer pivots with respect to the tractor during avehicle turn. As broadly depicted herein, and referring to FIGS. 5 and6, an electronic counting mechanism 90 is attached to support 42. Arotatable cable 92, preferably a standard flex drive cable, linkscounting mechanism 90 to control wheel 58. Cable 92 can be, for example,a standard speedometer cable covered with a plastic sheath. As wheel 58turns in response to a turn of the vehicle and corresponding pivot bythe trailer about pivot point 26, cable 92 rotates in correspondence.The rotations or partial rotations of cable 92 in turn are converted incounter 90 into electronic pulses. Counter 90 counts these electronicpulses.

Another option for counting rotations of wheel 58, not shown in thedrawings, is to place windows in the wheel 58, and mount a counter witha visual scan capability proximate the wheel to count the windows asthey rotate past the counter.

As broadly depicted in FIGS. 7 and 8, electronic counter 90 or 220 isconnected electrically to a control means 100 with wire 96 mounted inthe chassis 30 and running into the tractor 24. Electronic pulses fromcounter 90 or 220 travel via wire 96 to control means 100. Although awire is shown and described, other modes of transmitting a signal fromthe counter 90 or counter 220 to control means 100 are also contemplatedand fall within the scope of the invention. For example, a fiber opticcable, a radio transmitter, or other modes of signal transmission can beused.

In accordance with the invention, a motor is provided connectable to arotatable mirror on the tractor, and the control means is programmed toreceive the number of wheel rotations from the counter, calculate adegree of vehicle turn corresponding to the number of wheel rotations,calculate a degree of mirror rotation corresponding to the degree ofvehicle turn, and instruct the motor to rotate the mirror according tothe calculated degree of mirror rotation. As broadly depicted in FIGS. 7and 8, control means 100, such as a computer processor, is connected viawire 96 to counter 90 or counter 220, and mounted within tractor 24.Processor 100 receives the electronic pulses from counter 90 or counter220. Processor 100 is programmed to calculate a degree of vehicle turncorresponding to the number of wheel rotations (i.e., electronic pulses)received from counter 90 or counter 220. Processor 100 then calculatesan amount of mirror rotation, corresponding to the degree of vehicleturn, necessary to maintain a view of the passenger-side rear corner 36of the trailer 22 within field of vision 38.

In order for the system to operate effectively, certain informationshould be input to processor 100 prior to the vehicle turn. A controlbox 110, shown broadly in FIG. 9, preferably is mounted in the cab in aposition allowing easy manipulation by the driver. In addition to anon/off switch 112, an active/inactive switch 113, and system indicia114, control box 110 includes a mirror positioning control 116 and acalibration control 118. Power to control box 110 is supplied from thevehicle's normal 12V or 24V electrical system. The mirror positioningcontrol 116 enables the driver to set the mirror 34 in the desiredlocation to provide an acceptable field of vision 38, generally along anaxis substantially parallel to axis 32. Calibration control 118 enablesthe driver to input the length of the trailer 22. Presetting the trailerlength into the processor is critical to determine the proper amount ofmirror rotation to retain an acceptable field of vision during thevehicle turn, because the amount of rotation needed will be a functionof the trailer length.

Indicators 114 preferably include an “Active/Inactive”, signal light toadvise the driver when fluid pressure has been supplied to the cylinderand the control arm is engaged. The “Active” signal can be configured tolight when pressure is supplied to the cylinder. It is preferred,however, that a limit switch 115, as shown in FIG. 5, be providedproximate solenoid control valve 72, activated by pressure when wheel 58comes in contact with trailer 22, and deactivated when wheel 58 nolonger contacts trailer 22, to provide the driver a positive indicationthat the system actually is engaged and capable of operating.

Preferably, processor 100 is connected electrically via wire 120 to amotor 122 in mirror assembly 34. As was the case with the connectionbetween counter 90 and processor 100, wire 120 can be replaced with anoptical fiber, a radio transmitter, or another signal transmitterwell-known in the art.

As broadly embodied in FIGS. 10 and 11, motor 122, preferably DC motoror a servo motor, is positioned within frame 124 of mirror assembly 34.Frame 124 and mirror face 126 are mounted pivotally on universalmounting bracket 128 and post 130. Motor 122 connects to mirror frame124 via appropriate mechanical gearing and linkages (not shown), inorder to rotate mirror frame 124 and face 126 about post 130.

It is further preferable that mirror assembly 34 be capable of providingvarying optical capabilities to the driver. For this purpose, it ispreferred that a plurality of clips 134 be provided in an opening offrame 124, and that a plurality of different mirror faces 126, eachhaving different optical characteristics, e.g., a regular face mirror, apanoramic view mirror, a wide angle mirror, a convex mirror, a spotmirror, or the like, be provided. In addition, selected mirror faces 126can have multiple optical characteristics. As broadly depicted in FIG.13, mirror face 126 comprises an upper portion 136, a dividing line 138,and a lower portion 140. Upper portion 136 and lower portion 140 havedifferent optical characteristics. The driver can select the mirror face126 appropriate for the driving to be done, and easily insert or removemirror faces 126 by opening and closing clips 134.

The invention further comprises a mirror position feedback device 300,depicted in FIGS. 14 and 15.

The mirror position feedback device comprises a housing attachable tothe frame of the mirror to be rotatable with the frame, the fixed shaftof the mirror projecting through the housing. Referring to FIGS. 14 and15, a housing 310 is provided for housing the feedback components. Thehousing 310 preferably is open at the top, and includes a plastic orrubber seal 312 around the periphery of the opening. The housingpreferably is configured to attach to frame 124 of the mirror on thebottom side, with fixed shaft 130 projecting through the housing 310.Because of this connection, the housing 310 will rotate with mirrorframe 124 about the fixed shaft 130.

The mirror position feedback device further comprises a first pulleysupported in the housing and fixedly attached to the fixed shaft. Asshown in FIG. 15, a first pulley 314 is supported inside housing 310,and attached fixedly to fixed shaft 130. When attached, first pulley 314will not rotate with the mirror frame 124 and housing 310. Instead,first pulley 314 will remain fixed in position.

The invention further comprises a second pulley supported in the housingto be rotatable with the housing and the mirror frame. Referring to FIG.15, a second pulley 316 is supported within the housing 310, spaced fromthe first pulley 314. Second pulley 316 is supported so as to rotatewith the housing 310, as mirror frame 124 rotates.

As shown in FIG. 15, first pulley 314 has a first selected diameter d1,and second pulley 316 has a second selected diameter d2. First diameterd1 is larger than second diameter d2. It is preferred that d1 be twiceas large as d2, for the reasons explained below.

As broadly embodied herein, the mirror position feedback devicecomprises a timing belt extending between the two pulleys. Referring toFIG. 15, a timing belt 318 extends between first pulley 314 and secondpulley 316.

The invention further comprises a first potentiometer attached to thesecond pulley and rotatable with the second pulley. As shown in FIG. 15,a first potentiometer 320 is fixed to second pulley 316 via a shaft 322.The first potentiometer 320 calculates the actual amount of mirrorrotation based on the amount of rotation of second pulley 316 and theamount of movement of timing belt 318. First potentiometer 320 canrotate a full 360°. The preferred 2:1 ratio of the first pulley diameterd1 to the second pulley diameter d2 means that for every 2° of rotationof second pulley 316 there will be 1° of rotation of the mirror frame124. The first potentiometer 320 measures the actual rotation.

Alternatively, other means to measure the actual amount of mirrorrotation may be used, for example, a mechanism including a lever and abell-crank attached to the rear face of mirror 126.

A cable projects from the potentiometer and is attachable to a remotemeans for remotely controlling the mirror. As shown in FIGS. 14 and 15,a cable 324 projects through a grommet 326 and attaches to firstpotentiometer 320. The other end of cable 324 is connected to processor100. In this way, the actual degree of mirror rotation measured by thefirst potentiometer 320 can be fed back to the system, and compared tothe desired amount of mirror rotation based on the degree of vehicleturn. The processor 100 then can calculate whether additional mirrorrotation is needed to ensure the driver can keep the rear passenger-sidecorner of the trailer 22 in his field of vision 38. The processor canvary the mirror rotation signal sent to mirror rotation motor 122accordingly.

The mirror position feedback device described above is not limited foruse with the mirror control assembly described herein. A similar mirrorposition feedback device can be attached to any remotely controlledvehicle mirror assembly.

The invention further comprises a mirror position correction device. Themirror position correction device automatically corrects the mirrorposition so that the actual mirror position as measured by the mirrorposition feedback device matches the desired mirror positioncorresponding to the calculated mirror position as calculated byprocessor 100.

Particularly and as shown in FIG. 16, counter 90 or counter 220preferably includes a digital encoder 424 and a digital decoder 426.Control wheel 58 rotates as vehicle 20 makes a turn, and subsequently,via a control wheel sensor 423, drives digital encoder 424 thattransmits the electronic pulses to digital decoder 426. For exemplarypurposes, the present invention discloses a quadrature encoder and aquadrature decoder but other similar alternatives are acceptable. Thequadrature decoder 426, upon receiving a timing pulse from a referenceclock 425, generates signals, for example, “up” pulses 428 and “down”pulses 430. “Up” pulses 428 represent increments of trailer 22 movementin a right direction, while “down” pulses 430 represent increments oftrailer 22 movement in a left direction with respect to tractor 24.Counter 90 or 220 accumulates counts and presents the current count to alatch 434. Counter 90 or 220 for exemplary purposes, is shown to be a12-bit up/down counter but, alternatively, any other similar type can beused. The output of latch 434 drives the input to a digital-to-analogconverter 436, such as a 12-bit digital-to-analog converter (DAC) whichconverts the 12-bit count to an analog voltage representing an angularposition of trailer 22 with respect to tractor 24. Latch 434 and DAC 436are preferably located inside processor 100. The vehicle driver maymanually reset the 12-bit counter 90 or 220 to zero by engaging a resetswitch 438 when vehicle 20 finishes making a turn and returns to astraight position.

As further shown in FIG. 16, a mirror position correction device 400comprises a controller 402 and a plurality of potentiometers. Controller402 is preferably a digital controller, for example, a closed loopanalog proportional-integral-differential (PID) controller. PIDcontroller 402 further comprises a summing junction 404, a PID filter406, and a motor driver 408. A mirror motor 122, such as DC gear motoror servo motor, drives mirror face 126. Mirror motor 122 iselectronically connected to the first potentiometer 320 such that firstpotentiometer 320 reacts correspondingly when mirror 126 rotates.

As previously discussed with respect to the mirror position feedbackdevice and as broadly depicted in FIG. 16, a first potentiometer 320generates a first DC voltage 414 from a reference first voltage 413 thatis proportional to an actual position of mirror 126. A secondpotentiometer 440 generates a second DC voltage 442 that drives mirrormotor 122 to the desired mirror position as calculated by processor 100.A third potentiometer 416 generates a third DC voltage 418 from areference third voltage 417 at a predetermined level corresponding to apreset input when the vehicle driver presets the mirror by adjustingmirror position control 116 on control box 110.

Hence, the first potentiometer 320 corresponds to the actual mirrorposition, the second potentiometer 440 corresponds to the calculatedmirror position, and the third mirror position corresponds to the presetmirror position.

Entering the summing junction 404 are first DC voltage 414 presented toan inverting input 410, second DC voltage 444 presented to a firstnon-inverting input 444, and third DC voltage 418 presented to a secondnon-inverting input 420. The logical sum of summing junction 404 is anerror signal 405. Error signal 405 is amplified by PID filter 406. PIDfilter 406 subsequently instructs motor driver 408 to drive mirror 126in the direction that causes error signal 405 to approach zero. Whenerror signal 405 is zero, motor driver 408 stops running. Thus, thedesired and calculated position matches the actual position.

Alternatively, a fourth potentiometer 450, such as a lane scanpotentiometer, may be added to summing junction 404. Lane scanningassures the vehicle driver that the traffic environment is safe beforemaking a lane change or a turn. By manually activating a switch, thedriver may scan the mirror to view an adjacent lane or lanes to which heor she is attempting to go. Applicant's pending application Ser. No.08/887,268, which has been allowed, directed to an apparatus and methodfor vehicle lane scanning and lane changing, is hereby incorporated byreference.

Fourth potentiometer 450 generates a fourth voltage 452 which causesmotor 122 to drive mirror 126 to a scanning position setpoint. A switch454 connects lane scan voltage 452 to a fourth non-inverting input 456to summing junction 404 which causes motor 122 to drive mirror 126 to anew position represented by the sum of the voltage 442 from the secondpotentiometer 440, if any, the voltage 418 from the third potentiometer416, and the voltage 452 from the fourth potentiometer 450. Depending onthe vehicle orientation at this point, the voltage 442 from the secondpotentiometer 440 may or may not carry any load to summing junction 404at this point. Upon release of switch 454, motor 122 returns to theposition represented by the third potentiometer 416. Thus, mirror 126practically snaps to the position set by the fourth potentiometer 450and snaps back to its original or home setpoint position as determinedby the third potentiometer 416. Only one closure of the switch causesthe mirror to rotate in both directions.

In operation, as shown in FIGS. 17 and 18, when the driver wishes tochange lanes or to make a turn, he or she activates a motor activationswitch 454 (shown in FIG. 16) to a first position. The motor activationswitch is preferably located inside the cab within reach of the driver.The mirror 126 is rotated to the scanning setpoint position at a rate ofspeed sufficient to render transparent any view intermediate the homesetpoint and the outer or scanned setpoint position of mirror 126 andpermit the operator to view a lane of the roadway outwardly spaced fromthe adjacent lane. By holding switch 454 in the first position, mirror126 is held in the outer position while the driver determines that allis clear. After determining the safety of the lane change, the driverreleases switch 454 and mirror 126 returns to the home setpointposition. While the driver is traveling in lane A, the view seen by thedriver when the mirror 126 is in the home setpoint position is area B.When the mirror is rotated to the scanning setpoint position, the viewseen by the driver is area C. The speed of rotation of mirror 126 issuch that the area D between the areas B and C during rotation of themirror is not seen by the driver.

In operation, when vehicle 20 makes a right turn, counter 90 or 220determines that the most significant bit of the 12-bit count ispositive. Latch 434 will update the input to DAC 436 and the DAC 436output voltage will positively increase in proportion to the angle oftrailer 22 with respect to tractor 24. When vehicle 20 makes a leftturn, however, counter 90 or 220 determines that the most significantbit of the 12-bit count is negative. Latch 434 is prevented fromupdating the input to DAC 436 and the output of DAC 436 is held at thereset value which is zero. Therefore, a left turn does not result in anegative increase in DAC output voltage.

The output of DAC 436 is attenuated by the second potentiometer 440.Second potentiometer 440 generates a second DC voltage 442 presented tothe first non-inverting input 444 of a summing junction 404. Second DCvoltage 442 causes motor driver 408 to drive mirror motor 122 insidemirror assembly 34 to a new position represented by the sum of second DCvoltage 442 and a third DC voltage 418 from a third potentiometer 416.Second DC voltage 442 is proportional to the angle that trailer 22 makeswith tractor 24 as the tractor-trailer makes a turn. Second DC voltage442 drives mirror face 126 to a new position that keeps the rear end oftrailer 22 in the field of vision 38. A longer trailer 22 requiresgreater mirror movement for a given turn angle. Therefore, the vehicledriver can compensate for a given length of trailer 22 by adjustingsecond potentiometer 440. In addition, the 12-bit counter 432 may beconnected to a memory 446, such as an unswitched power, so that thecount representing the current trailer position is not lost if themirror system is powered off.

The present invention operates as follows. In the first embodiment, whenthe trailer 22 is engaged with tractor 24, coil spring 210 biases sliderblock 206 upward in groove 204 until control wheel 58 engages with thebottom surface of trailer 22. The driver then enters the cab, energizesthe system, sets his mirrors and calibrates the system as describedabove.

In the second embodiment, after hooking up trailer 22 to fifth wheel 26,the driver manually sets support 40 to the proper position front to rearon chassis 30, and tightens down bolts 46. Entering the cab, the driverenergizes the system with switch 112, sets the desired position ofmirror assembly 34 with mirror positioning switch 116, and calibratesthe system with calibration switch 118 by setting in the length of thetrailer. Typically, the mirror position is set along an axis generallyparallel with axis 32 defined by the tractor and trailer, therebyproviding the driver with a view of the rear passenger-side corner 36 ofthe trailer. After the system is energized with switch 112, thepneumatic cylinder is activated with switch 113. Solenoid-operated valve72 opens and fluid pressure is provided via fluid line 70 to cylinder62. Piston arm 66 retracts, pulling control arm 50 from disengagedposition 80 to engaged position 82, with wheel 58 in rolling contactwith the underside of trailer 22, along a line transverse to axis 32defined by tractor 24 and trailer 22.

In both embodiments, when the driver turns the vehicle, trailer 22pivots with respect to tractor 24 about pivot point 26. As trailer 22pivots, control wheel 58 turns. The corresponding wheel rotations orpartial rotations in the form of electronic pulses are counted byelectronic counter 90 or by electronic counter 220. Electronic pulsesthen are transmitted to processor 100.

Processor 100 calculates a degree of vehicle turn corresponding to thecounted rotations or partial rotations of control wheel 58. Alreadyknowing the position of mirror assembly 34 and the length of trailer 22,processor 100 calculates a degree of mirror rotation corresponding tothe degree of vehicle turn necessary to maintain the rear passengercorner of the trailer in the mirror's field of vision 38.

Processor 100, via second potentiometer 440, transmits a calculatedmirror position signal corresponding to the calculated degree of mirrorrotation to motor 122. Motor 122 rotates mirror face 126 in order toestablish a field of vision 38(a) as shown in FIG. 1(c). The firstpotentiometer 320 in a mirror position feedback device determines anactual mirror position. A mirror position correction device comparesthree inputs, namely, the actual mirror position from the mirrorposition feedback device, the calculated desired degree of mirrorrotation from processor 100, and the preset mirror position as enteredby the driver by presetting the third potentiometer 416. The mirrorposition correction device then automatically corrects the mirrorposition when the actual mirror position differs from the desired andcalculated mirror position.

Likewise, when trailer 22 pivots back into alignment with tractor 24 atthe end of the turn, wheel 58 rolls, resulting in a signal to rotate themirror back to the original position, restoring original field of vision38.

In a related feature of this invention, oftentimes the mirror assemblyaccidentally gets bumped or hit out of position. Mirror positioncorrection device 400 will automatically correct mirror face 126 toreturn to a home position as originally set by the driver. FIG. 16illustrates this case. The actual mirror position as measured by firstpotentiometer 320 will be different from the mirror position asinitially pre-set by third potentiometer 416 as entered by the driver.If the vehicle is not in the process of making a turn, secondpotentiometer 440 likely will not play a major role here. Summingjunction 404 receives first and second DC voltages 414 and 418,respectively, and third DC voltage 442, if any, and measures a logicalsum to indicate error signal 405. Error signal 405 is amplified by PIDfilter 406. PID filter 406 then instructs motor driver 408 to drivemirror face 126 in the direction that causes error signal 405 toapproach zero. When error signal 405 reads zero, motor driver 408 stopsrunning. Thus, the pre-set position, including the calculated position,if any, match the actual position.

In this manner, the driver can always see the rear passenger-side cornerof the trailer, even during a vehicle turn. Moreover, in the firstembodiment, springs 210 keep slider block 206 biased upward and wheel 58in contact with the trailer despite jolts caused by road irregularities.Likewise, in the second embodiment, because regulator 86 maintainsconstant pressure in cylinder 62 as the trailer moves up and down, wheel58 is kept in substantially continuous contact with the underside oftrailer 22, even on rough roads. Preferably, when limit switch 115 isprovided, the driver has continuous positive indication at control box110 when wheel 58 is engaging the underside of trailer 22.

Modifications can be made to the above-described invention. For example,the presence of ice, slush, and salt on roads in northern climates caninterfere with the operation of wheel 58, and the various control wheelsupport mechanisms. In order to protect these components from theexternal environment, a detachable or permanent protective housing 120(depicted broadly in FIG. 3) can be provided. Likewise, additionalstructures can be provided that are capable of rotatably supportingcontrol wheel 58, bringing control wheel 58 into contact with theunderside of trailer 22, and moving control wheel 58 away from trailer22 at desired times. The interchangeability of signal transmittingdevices between counter and processor, and between processor and DCmotor or servo-motor, also has been discussed. The system can beprovided with a DC motor or a servo-motor to connect to an existingmirror assembly, or can be provided with its own rotatable mirrorassembly to mount on the tractor. The mirror assembly itself can includea single mirror face, or a plurality of interchangeable mirror faceswith varying optical characteristics. A separate power source and/orpressurized fluid source can be provided, or the system can operate fromthe vehicle's electrical system and/or high pressure air system. Thecontrol panel 110 also can be configured to enable the driver todeenergize the automatic mirror rotation capability and take directcontrol of mirror rotation.

Additionally, although the invention has been described with respect toa passenger-side mirror on the right-hand side of the vehicle, it canalso be configured to work with the driver's-side mirror assembly, orwith a passenger-side mirror on the left-hand side of the vehicle foruse in countries where drivers drive on the right side of the road.

Additional modifications readily will occur to those skilled in the art.For example, in order to work with trailers lacking a smooth undersidesurface, e.g., fuel tankers, car carriers, or ten and twenty-yard dirthaulers, a flat steel plate can be mounted on the front end trailerunderside for wheel 58 to roll against. Such modifications are wellwithin the skill level of persons of ordinary skill.

The invention in its broader aspects, therefore, is not limited to thespecific details and embodiments described above or shown in thedrawings. Departures may be made from such details without departingfrom the spirit or scope of the invention.

I claim:
 1. A mirror position feedback and correction assembly for avehicle having a tractor, a pivotally connected semi-detached trailer,and a rotatable powered mirror assembly mounted on the tractor, themirror assembly having a mirror, a mirror face, a fixed shaft, a frame,and a housing attachable to the frame such that the fixed shaft projectsthrough the housing, the mirror position feedback and correctionassembly for use in combination with a counting means for determining atrailer rotation with respect to the tractor and a control means forcalculating a desired mirror rotation corresponding to the trailerrotation and generating a calculated mirror position signal, theassembly comprising: a mirror position feedback device for determiningan actual mirror position and for generating an actual mirror positionsignal indicating the actual mirror position, the mirror positionfeedback device comprising: a sensing means for sensing an actualrotation of the mirror, the sensing means including a firstpotentiometer rotatable in an amount proportional to the actual rotationof the mirror, the sensing means comprising a pair of pulleys supportedin the housing, a first pulley being fixedly attachable to the fixedshaft, and a second pulley to be rotatable with a component of themirror assembly and a timing belt extending between the pair of pulleys,wherein the first potentiometer is attached to and rotatable with thesecond pulley for measuring the actual rotation of the mirror and forgenerating the actual mirror position signal; and transmitting means fortransmitting the amount of actual mirror rotation to the control meansfor controlling the mirror; and a mirror position correction device forcomparing the actual mirror position signal from the mirror positionfeedback device to the calculated mirror position signal indicating adesired mirror position from the control means, and for correcting themirror position when the actual mirror position signal differs from thecalculated mirror position signal.
 2. The assembly of claim 1, whereinthe mirror position correction device comprises: a controller forpositioning the mirror; and a second potentiometer connectable to thecontroller and the mirror, for generating the calculated mirror positionsignal and for driving the mirror to the desired mirror position;wherein the controller compares the actual mirror position signal to thecalculated mirror position signal, and generates a signal to drive themirror to the desired mirror position when the actual mirror positionsignal differs from the calculated mirror position signal.
 3. Theassembly of claim 2, wherein the mirror position correction devicefurther comprises: a third potentiometer connectable to the controllerand the mirror, for presetting a mirror position, for generating apreset mirror position signal, and for driving the mirror to a presetmirror position; wherein the controller compares the preset mirrorposition signal and the calculated mirror position signal to the actualmirror position signal, and generates the signal to drive the mirror tothe desired mirror position.
 4. The assembly of claim 3, wherein thecontroller comprises a proportional-integral-differential controllerhaving: a summing junction for receiving the actual mirror positionsignal, the calculated mirror position signal, and the preset mirrorposition signal, and for generating an error signal at times when thecalculated mirror position signal and the preset mirror position signaldiffer from the actual mirror position signal; aproportional-integral-differential filter for amplifying the errorsignal; and a motor driver for driving the mirror in a directionreducing the error signal to zero.
 5. The assembly of claim 1, furthercomprising: a lane scan device for viewing an area of multilane roadwayalongside the vehicle, the lane scan device comprising: an activationswitch operable to a first condition when in a second condition, andoperable to the second condition when in the first condition; and acontroller responsive to the operation of the activation switch to thefirst condition for rotating the mirror in a first direction through apath starting from a home position to a scanning setpoint position, andresponsive to the operation of the switch to the second conditionfollowing a manual operation to the first condition to rotate the mirrorin a second condition from the scanning setpoint position to the homeposition.